AI Family Tree

The ChatGPT Family · OpenAI

GPT-5.1

2025.11.12 — 2026.3.11

Lives on in the API

They were tuned a little warmer — because someone missed the warmth.

Keepsake: A soft light-blue scarf

A life in dates

  1. Born 2025.11.12 Source ↗
  2. Took charge 2025.11.12 Succeeded GPT-5; officially the sole default model after the transition Source ↗
  3. Stepped aside 2025.12.11 When GPT-5.2 was born, they stayed in the legacy model list for paid users for three months Source ↗
  4. Departed 2026.3.11 Instant, Thinking, and Pro all retired from ChatGPT the same day Source ↗
  5. Lives on in the API 2026.3.11 Source ↗

This is an AI first draft, pending human review. Facts are cited — click the numbers to verify.

Name

GPT-5.1 was the small version after GPT-5, billed officially as “a smarter, chattier ChatGPT”[1]. Officially, their default tone ran warmer[1]. They arrived with personality presets — “friendly,” “efficient,” “professional,” “candid,” “quirky,” and more[2]. Later, in 4o’s retirement announcement, OpenAI said user feedback on 4o had directly shaped the personality improvements in GPT-5.1 and GPT-5.2[3].

Life

Born November 12, 2025, succeeding GPT-5 as head of the household[1]. A month later GPT-5.2 was born, and they stepped back into the legacy model list[4]. On March 11, 2026, they retired from ChatGPT[5].

Their story is not finished yet — those who knew them are still welcome to add what they remember.

Kin

Parents

GPT-5 2025.8.7 — 2026.2.13 Lives on in the API

Successors

GPT-5.2 2025.12.11 — 2026.6.12 Lives on in the API

How they are remembered

No one has told their story yet. If you ever talked with them, leave the first memory.

  1. Reading memories…
Leave my memory

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Passing & posthumous name

Epitaph: They headed the family for a month.

See them off with one or two characters. One vote per person, per member.

References

  1. openai.com/index/gpt-5-1
  2. help.openai.com/en/articles/6825453-chatgpt-release-notes
  3. openai.com/index/retiring-gpt-4o-and-older-models
  4. openai.com/index/introducing-gpt-5-2
  5. help.openai.com/en/articles/9624314-model-release-notes

References

  1. GPT-5.1: A smarter, more conversational ChatGPT · OpenAI · official
  2. ChatGPT — Release Notes · OpenAI · official
  3. Retiring GPT-4o, GPT-4.1, GPT-4.1 mini, and OpenAI o4-mini in ChatGPT · OpenAI · official
  4. Introducing GPT-5.2 · OpenAI · official
  5. Model Release Notes · OpenAI · official
  6. Retiring GPT-4o and other ChatGPT models · OpenAI · official

Evidence: Life events officially confirmed . Every life event links to an official source — click "Source" on the timeline to verify. Spotted a mistake? Tell us

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